Well, I don't think being simpler makes it any less enjoyable. I like both Dark Souls and the Elder Scrolls, but I find the ES universe a lot more enjoyable. And maybe being simpler is the reason it is used so much for VR. Simulating the more complex combat systems of games like Dark Souls might be difficult for controllers like the Hydra Razer, Wii Remotes and such. The STEMS could possibly change that, but for demonstration purposes I can isee why Skyrim must be a very popular choice. It is a recent, popular game with great graphics and a simple combat system.
I'm not referring to things that use peripherals. I'm talking about the standard idea of VR, but even with that, Skyrim is still incredibly simple. It's not a matter of it being better or worse because of its simplicity (nor do I think that's the case) but rather whether it's worth bringing to the virtual reality realm. In the case of peripheral use, it's very "press this button to attack", and that's about it, and because the direction in which you attack isn't a matter of importance, it would pretty much employ the waggle, in that the player's input can be done anyway and have the same effect, and upon realizing this, the player would find about as much enjoyment in it as pressing a button with a slight change of pace. It'd be the same for body motion as well. Dark Souls really isn't that complex, ES is just one of the much less involved ARPGs you can find.
Plus, when talking about Elder Scrolls in general, you have to consider that what people have fun with is the exploration with the thrill of survival (which is largely what makes mods so popular). People like to fight, but it's not the fighting system that people like about Elder Scrolls, it's the system and the world built around it. Seeing Cyrodiil, which is personally my favorite region for a number of reasons, in first person would indeed be breathtaking, but that's when you really create a division. People like Dark Souls because of its difficulty, and that largely hinges on its gameplay. It's an intuitive system that requires more player input than something like Elder Scrolls, and because of that, it's the more attractive game for someone who wants to have fun with the concept of immersing themselves into a dark and almost terrifying world where they need to harness the game to survive. The difference is, Elder Scrolls is popular because of concept execution, and being able to immerse oneself in the often times beautiful worlds that they craft is enticing. Dark Souls is popular because of concept execution as well, but where ES places its emphasis on the world, Dark Souls practically hangs onto its gameplay and difficulty, and thus which one seems more attractive really depends on what the player wants out of the VR experience or, in general, what they want out of the game.